Plastic fragments and microplastics pulled from the Great Pacific Garbage Patch in 2018 sit among natural matter at the bottom of a trawl net.Tabor Wordelman

Plastics surround us. We eat out of plastic, store food in it, buy food wrapped in it, put it in our eyes in the form of contact lenses, drink out of it — it’s inescapable and, admittedly, incredibly useful. But a growing body of evidence shows that plastics are likely harming human health in a number of ways, and in the United States, there’s little government oversight to stop it.

We have so much plastic because it’s durable, useful in many forms, and often cheap to purchase. But in the last decade, scientists have discovered that the chemicals that hold plastics together are likely having a negative impact on human health. Beyond limiting exposure altogether — which would prove difficult — there’s only so much we can do to protect our bodies from these impacts, which may be gradual, but can also be long-lasting.

Plastics are held together with chemicals called plasticizers, and experts have expressed great concern about two: bisphenol-A (known as BPA) and phthalates. BPA and phthalates can be found in reusable food and drink containers, sports equipment, automobiles, toys, vinyl floor covering, detergents, shampoo, soaps, and hair sprays. These plasticizers are classified under the umbrella of “endocrine disrupting compounds,” according to Stephanie Engel, PhD, professor of epidemiology at the University of North Carolina at Chapel Hill. “[That] basically means that they can either act like or block the action of our natural hormone system,” Dr. Engel tells Teen Vogue.

When we heat plastic in the microwave or reuse single-use water bottles, for example, these compounds find a way into the human body and can cause a variety of health effects over time.

“Trials have shown that BPA can have implications on kidney function as well as metabolic functions,” Dr. Gabriel Olaiya, who works with the National Health Service in the United Kingdom, tells Teen Vogue. “Studies have shown that it can cause [...] the early onset of puberty in young children, as well as actually causing [an] increased instance of anxiety and behavioral problems in unborn children when their mothers are exposed to the plastic.”

BPA and other endocrine disruptors can also exacerbate conditions such as diabetes, which causes kidney damage, Dr. Olaiya says. According to a number of studies recognized by the U.S. National Institutes of Health, BPA is also associated with increased cancer risk and “early sexual maturation, decreased male fertility, aggressive behavior,” and other effects.

Dr. Engel worked on a study that evaluated the effects of pregnant women’s exposure to phthalates on the neurodevelopment of their children, from birth to age 10. She ranked the women by the degree of their exposure — some women were exposed more, some less — by measuring a biological marker in their urine.

The study found that the children of pregnant women who had the highest exposure to a phthalate called diethylhexyl phthalate, or DEHP, “had about three times the risk of being diagnosed with ADHD in childhood as compared to women in the lowest exposure category,” Dr. Engel says. “That very much aligns with a growing body of evidence linking exposure to some specific phthalate with neurodevelopmental effects in later life.”

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In short: Dr. Engel found a connection between a pregnant woman's exposure to a chemical found in plastic and the child's risk of developing ADHD.

She notes that it’s impossible to have a control group of people who aren’t exposed to these chemicals, and such a control group wouldn’t reflect our “lived experience.” In reality, Dr. Engel says, “we’re all kind of living in a chemical soup here — it’s just part of modern life.”

To account for this, Dr. Engel measured as many as 20 different chemicals that could travel together in different products. She tried to “disentangle” the effects of exposure to one in relation to the women’s exposure to all the other chemicals; that’s important because everyone has a different level of plastic exposure, depending on their lifestyle. Plastics can be present inside our bodies not just in contact lenses, but breast implants, in microfibers from the water we drink, and microplastics in the fish and salt we eat.

More than eight million tons of plastic end up in our oceans every year, according to Plastic Oceans International. Much of that plastic is litter and plastic from landfills that found its way into a body of water. Arizona State University doctoral student Charles Rolsky, who studies plastic pollution in the ocean, tells Teen Vogue that microplastics, or plastics that have broken up into extremely small particles, are found on the bottom of the ocean. Those microplastics act as a “vehicle for contaminants,” or common pollutants, and can be eaten by ocean-floor dwellers like crabs, which are then eaten by something bigger. The higher up the food chain you go, the more concentrated those contaminants become, Rolsky explains.

“By the time [contaminants] reach some big whale or shark or even [a] human, there’s a decent chance that it has accumulated to a level that could be harmful,” Rolsky says. There’s no clear evidence regarding the large-scale health impacts of microplastics, he says, but the available research doesn’t paint a positive picture. “We piece together that plastics like contaminants. We piece together that contaminants cause issues. We also factor in how prevalent plastics are in the ocean. And so when you add all of those together, you’re just creating this scenario that’s very scary for any ecosystem where it’s found.”

Greenpeace campaigners examine microplastics collected in a trawl net and pulled from the Great Pacific Garbage Patch in 2018.

Tabor Wordelman

When it comes to the health effects of plastics, there is still a lot that is unknown. That scares experts because regulations of potentially dangerous plasticizers historically haven’t been passed until years after it was already widespread in plastics. For example, the Food and Drug Administration banned the use of certain BPA-based materials in baby bottles, sippy cups, and infant formula packaging in 2012, after years of pressure from scientists and Congress.

Dr. Engel says that in 2010, after companies voluntarily removed BPA from some children’s products, like baby bottles, many manufacturers simply replaced it with a very similar compound called bisphenol-S. “And, it turns out, 10 years later, it actually might be more harmful than the chemical that it replaced,” Dr. Engel says. “We call it ‘regrettable substitution’: A chemical is replacing another one and it turns out the new guy is actually worse than the one that was removed. Companies can say that a product is BPA-free, but that doesn’t mean that it is free of compounds with similar or worse biological effects.”

When it comes to proving the health effects of the chemicals in plastics, Dr. Engel says the burden is currently on the consumer, which is a problem, because the chemicals are in building materials, personal-care products, and the lining of cans — things you wouldn’t think contain plastic. “I would say the prudent move is to reduce exposure where you can and try to make choices — with the products you use and the products you buy — that are as plastic-free as possible,” Dr. Engel says. For example, use a stainless steel water bottle and store food in glass instead of plastic.

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In terms of protecting yourself long-term, Dr. Engel says that’s going to take changes at state and federal levels. "We need to pressure our elected officials to develop some common sense legislation that can address not just one chemical, but the [broader] issue of regrettable substitution and how we protect consumers,” she says. “Putting all of that responsibility on the shoulder of the consumer is just unfair, because we have no idea what products these chemicals are in."

We have systems in place to protect consumers before new drugs enter the market, Dr. Engel points out, adding that pharmaceutical companies are required to produce a large volume of safety data proving that the chemicals in their drugs are safe, and then they’re required to do post-marketing surveillance to make sure there isn’t an unexpected health outcome. “There is absolutely no reason in the world why the same system could not apply to chemicals,” she says.

Dr. Engel says the FDA and Consumer Product Safety Commission, two organizations that regulate the chemicals in plastics, have a haphazard and disjointed way of applying bans — like the ban on BPA in baby bottles. “We’re not banning a chemical — we’re banning a chemical in a specific product,” Dr. Engel says. BPA might be banned from being used in baby bottles, but it’s still present in other plastics that children and adults come into contact with.

“We probably don’t even know all of the chemicals that have been introduced into these products," she says. "Things are getting removed, but they’re being replaced by chemicals that we actually know even less about — and could be worse — and we don’t know.”

For more information on the global plastics crisis, read the rest of the Plastic Planet series.